1. Field of the Invention
The present invention relates to a wet-type image forming apparatus employing a wet-type electrophotographic technique.
2. Description of the Related Art
Image forming apparatuses employing an electrophotographic technique are widely used in the fields of facsimile machines, printers, copiers, and MFPs (Multi-Functional Peripherals). Recent image forming apparatuses are also used in the applications that require higher image quality and higher resolution, for example, such as office printers for bulk print or on-demand printers.
In recent years, in order to meet the needs of such applications, attention is focused on wet-type image forming apparatuses that use liquid developer including toner (also called toner particle) dispersed in insulating carrier liquid (see Japanese Laid-Open Patent Publication Nos. 2009-015351 and 2010-204467).
In wet-type image forming apparatuses, liquid developer drawn from a developer tank is carried on a surface of a developer carrier (developing roller). With the rotation of the developer carrier, the toner in the liquid developer carried on the developer carrier is conveyed to a development position where the developer carrier and an image carrier (photoconductor) face each other. The toner in the liquid developer carried on the developer carrier is then transferred from the surface of the developer carrier to the image carrier (photoconductor) with application of a development bias. An electrostatic latent image formed on the image carrier is developed as a toner image using the toner in the liquid developer.
The toner image on the image carrier is electrostatically transferred onto a surface such as recording paper or an intermediate transfer roller with application of a transfer bias (electrostatic transfer method). In the case where the toner image is transferred onto an intermediate transfer roller, the toner image transferred on the intermediate transfer roller is further transferred onto recording paper with application of another transfer bias.
The wet-type image forming apparatuses using liquid developer use toner particles having a small particle size when compared with dry-type image forming apparatuses. With the toner particles having a smaller particle size, fine portions of images can be expressed on recording paper. Therefore, the wet-type image forming apparatuses using liquid developer can be used to form high-quality images on recording paper.